阿尔泰山河谷林径向生长对气候的响应

Response of tree-ring growth to climatic factors in valley forest of Altai Mountain

阿尔泰山林区是新疆十分重要的生态屏障,研究阿尔泰山树木的生长规律及其对气候的响应十分重要。基于树木年轮学为基础,选择布尔津、哈巴河和北屯3个采样点,采用相关性分析及Mann-Kendall突变检验探究阿尔泰山河谷林径向生长变化特征及其对气候变化的响应。结果表明:(1)布尔津树轮宽度年表平均敏感度、标准差、树间相关系数和第一特征向量百分比最大,说明该标准化年表包含的气候信息最丰富的,其次是北屯。(2)河谷林3个样点树轮宽度指数变化均呈上升趋势,且经Mann-Kendall突变检验,哈巴河、北屯样点树轮年表的突变时间均在年平均气温和年降水量突变时间之后,说明树轮生长有“滞后效应”。(3)哈巴河样点树轮宽度指数与前一年降水量呈显著正相关(P<0.01),北屯样点树轮宽度指数与当年降水量呈显著正相关(P<0.01),说明树轮宽度指数与降水相关性较强,与气温相关性较弱。(4)布尔津树轮年表受温度影响大,从生长季开始到生长季中后期,均与气温呈显著正相关,北屯树轮年表与降水呈显著正相关,与生长季末期的平均温度呈显著负相关。研究表明即使在相似生境下树木生长的影响因素也不同,布尔津样点树木受到开始生长时温度和结束时降水的影响较大,而北屯和哈巴河受生长季降水因素影响更为突出。

Altai Mountain forest is a very important ecological barrier in Xinjiang.It is very important to study the growth mechanism of trees and their response to climate in the Altai Valley forest.Based on dendroclimatology,Burqin,Habahe and Beitun were selected as the sampling sites.Correlation analysis and Mann-Kendall mutation test were used to explore the characteristics of radial growth and its response to climate change in Altai Valley forest.The results showed that:①average sensitivity,standard deviation,inter-tree correlation coefficient and the percentage of the first eigenvector of the tree-ring width chronology of Burqin site are the largest,indicating that the standardized chronology contains the most abundant climate information,followed by Beitun site.②The tree-ring width index of the three sampling sites in the valley forest showed an upward trend.Mann-Kendall mutation test showed that the mutation time of the tree-ring chronologies of both the Habahe and Beitun sampling sites were after the mutation time of the annual average temperature and annual precipitation,indicating that the tree-ring growth had a“lag effect”.③The tree-ring width index of Habahe site was significantly positive correlated with the precipitation in the previous year(P<0.01),and the tree-ring width index of Beitun site was significantly positively correlated with the precipitation in the current year(P<0.01),indicating that the tree-ring width index had a strong correlation with precipitation and a weak correlation with temperature.④Through the whole growing season,there was a significant positive correlation between the tree-ring chronology and the temperature.The tree-ring chronology of Beitun site was significantly positively correlated with precipitation and negatively correlated with the average temperature at the end of the growing season.Studies have shown that even in similar habitats,the influencing factors of tree growth are different.The trees in the Burqin site are greatly affected by the temperature at the beginning of growth and the precipitation at the end of growth,while the Beitun and Habahe sites were more affected by the precipitation factors in the growing season.